文章目录
- 问题:点云与网格垂直
- 背景
- 解决方法:对点云坐标做变换,绕x轴旋转90度,将z轴指向上方
- 将pcd转成点云,在RVIZ中显示点云图
- 创建launch
 
- rviz显示
 
 
问题:点云与网格垂直
用lego-loam建图时用rosbag录制相关点云的话题,建图结束后用rosbag play将.bag包在rviz中显示,但是由于该话题的点云发布的frame_id=/camera_init,但是rviz中默认的坐标系是base_link,并且camera_init与base_link有旋转关系,因此导致点云在rviz中显示时与rviz网格线呈垂直关系,虽然rviz可以将默认显示的xy平面改成xz平面,让点云显示正常,但是此时不能在水平状态下左右旋转点云地图。
背景
ubuntu18.04+melodic
 lego-loam订阅话题/laser_cloud_surround后保存了四个.pcd文件:

 pcd保存的路径在utility.h文件中设置

解决方法:对点云坐标做变换,绕x轴旋转90度,将z轴指向上方
从PCD创建PointCloud2点云,然后再在rviz中显示
将pcd转成点云,在RVIZ中显示点云图
创建pcl_xy2xz.cpp文件:
#include<ros/ros.h>  
#include<pcl/point_cloud.h>
#include<pcl_conversions/pcl_conversions.h>  
#include<sensor_msgs/PointCloud2.h>  
#include<pcl/common/transforms.h>
#include<pcl/io/pcd_io.h>
      
int main (int argc, char **argv)
{  
    ros::init (argc, argv, "lego_loam");  
    ros::NodeHandle nh;  
    ros::Publisher pcl_pub = nh.advertise<sensor_msgs::PointCloud2> ("/lego_loam_with_c16/output", 10);  //待订阅的点云话题
    
    pcl::PointCloud<pcl::PointXYZ> cloud1,cloud2;  
    sensor_msgs::PointCloud2 output;  
    pcl::io::loadPCDFile ("/home/gyl/wheeltec_bag/lego-loam pcl/nosmog1/finalCloud.pcd", cloud1);	//自己的pcd路径
    Eigen::Affine3f transform_2 = Eigen::Affine3f::Identity();
    //绕x轴旋转一个theta角
    transform_2.rotate(Eigen::AngleAxisf(1.570795, Eigen::Vector3f::UnitX()));
    //执行变换
    //pcl::PointCloud<pcl::PointXYZ>::Ptr pPointCloudOut(new pcl::PointCloud<pcl::PointXYZ>());
    pcl::transformPointCloud(cloud1, cloud2, transform_2);
    pcl::toROSMsg(cloud2,output);// 转换成ROS下的数据类型 最终通过topic发布
    output.header.stamp=ros::Time::now();
    output.header.frame_id  ="/camera_init_xz";	//点云所在的坐标系,frame_id
    ros::Rate loop_rate(1);  
    while (ros::ok())  
    {  
        pcl_pub.publish(output);  
        ros::spinOnce();  
        loop_rate.sleep();  
    }  
    return 0;  
} 
catkin_make编译,结果报错:
CMakeFiles/urdf01_rviz_node.dir/src/pcl_xy2xz.cpp.o:在函数‘void pcl::createMapping<pcl::PointXYZ>(std::vector<pcl::PCLPointField, std::allocator<pcl::PCLPointField> > const&, std::vector<pcl::detail::FieldMapping, std::allocator<pcl::detail::FieldMapping> >&)’中:
/usr/include/pcl-1.8/pcl/conversions.h:108:对‘pcl::console::print(pcl::console::VERBOSITY_LEVEL, char const*, ...)’未定义的引用
/usr/include/pcl-1.8/pcl/conversions.h:108:对‘pcl::console::print(pcl::console::VERBOSITY_LEVEL, char const*, ...)’未定义的引用
/usr/include/pcl-1.8/pcl/conversions.h:108:对‘pcl::console::print(pcl::console::VERBOSITY_LEVEL, char const*, ...)’未定义的引用
CMakeFiles/urdf01_rviz_node.dir/src/pcl_xy2xz.cpp.o:在函数‘main’中:
/usr/include/pcl-1.8/pcl/io/pcd_io.h:56:对‘vtable for pcl::PCDReader’未定义的引用
/usr/include/pcl-1.8/pcl/io/pcd_io.h:208:对‘pcl::PCDReader::read(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, pcl::PCLPointCloud2&, Eigen::Matrix<float, 4, 1, 0, 4, 1>&, Eigen::Quaternion<float, 0>&, int&, int)’未定义的引用
collect2: error: ld returned 1 exit status
urdf01_rviz/CMakeFiles/urdf01_rviz_node.dir/build.make:127: recipe for target '/home/gyl/hello_w/devel/lib/urdf01_rviz/urdf01_rviz_node' failed
make[2]: *** [/home/gyl/hello_w/devel/lib/urdf01_rviz/urdf01_rviz_node] Error 1
CMakeFiles/Makefile2:5439: recipe for target 'urdf01_rviz/CMakeFiles/urdf01_rviz_node.dir/all' failed
make[1]: *** [urdf01_rviz/CMakeFiles/urdf01_rviz_node.dir/all] Error 2
Makefile:140: recipe for target 'all' failed
make: *** [all] Error 2
Invoking "make -j8 -l8" failed

原因就是CMakeLists.txt中没有配置好相关信息:
......
find_package(catkin REQUIRED COMPONENTS
  pcl_ros
  pcl_conversions
)
find_package(PCL REQUIRED QUIET)
catkin_package(
  DEPENDS PCL
)
include_directories(
  ${catkin_INCLUDE_DIRS}
  ${PCL_INCLUDE_DIRS}
)
link_directories(
	include
	${PCL_LIBRARY_DIRS}
)
add_executable(自己的项目名称 src/pcl_xy2xz.cpp)
target_link_libraries(自己的项目名称 ${catkin_LIBRARIES} ${PCL_LIBRARIES})
重新catkin_make编译就成功了。
创建launch
<launch>
	<!-- 运行创建的pcl_xy2xz.cpp文件 -->
    <node pkg="urdf01_rviz" type="pcl_xy2xz" name="pcl_xy2xz" output="screen" respawn="false"/>
	
	<!-- 使用octomap_server将点云地图转化为八叉树地图和占据栅格地图 -->
    <node pkg="octomap_server" type="octomap_server_node" name="octomap_server">
        <!-- resolution in meters per pixel -->
        <param name="resolution" value="0.1" />
        <!-- name of the fixed frame, needs to be "/map" for SLAM -->
        <param name="frame_id" type="string" value="/camera_init_xz" />
        <!-- max range / depth resolution of the kinect in meter -->
        <param name="sensor_model/max_range" value="50.0" />
        <param name="latch" value="true" />
        <!-- max/min height for occupancy map, should be in meters -->
        <param name="pointcloud_max_z" value="1000" />
        <param name="pointcloud_min_z" value="-1000" />
        <param name="ground_filter_angle" value="3.14" />
        <!-- topic from where pointcloud2 messages are subscribed -->
        <remap from="cloud_in" to="/lego_loam_with_c16/output" />
    </node>
	
	<!-- 启动rviz -->
    <node pkg="rviz" type="rviz" name="rviz" />
</launch>
rviz显示
点击add 按钮添加 “PointCloud2模块”
 设置topic为 “/lego_loam_with_c16/output”
 设置FixedFram为 “camera_init_xz”
点云显示:


 八叉树地图显示:


参考博客:
- 【激光SLAM】Lego_loam使用教程
- Octomap 在ROS环境下实时显示
- 使用octomap_server将点云地图转化为八叉树地图和占据栅格地图



















